1. Field of the Invention
The present invention relates to an apparatus for forming micro-holes on the outer circumference of the filtered section of a cigarette and, more particularly, it relates to an improvement of a system for controlling the apparatus to maintain the size of the micro-holes constant.
2. Description of the Related Art
In the case of some kinds of the filtered cigarettes, a plurality of micro-holes are formed on the outer circumference of the filtered section of each of the cigarettes. These cigarettes allow a large amount of air to be sucked into them when they are lit and smoked, thereby giving the smoker a lighter taste, diluting the smoke sucked into the mouth of the smoker, lowering the temperature of the smoke sucked, and reducing the amount of harmful components contained in the smoke.
The apparatus for forming the micro-holes on the cigarette is therefore incorporated into the cigarettes manufacturing apparatus. In the case of this micro-hole forming apparatus, a focused laser beam which has a certain light intensity is aimed at the cigarettes to form plural holes on the outer circumference of the filtered section of each of the cigarettes.
Cigarettes are produced in large quantities and at high speed. Therefore, there has been developed and provided an apparatus for forming the micro-holes on the cigarettes while carrying them at high speed. In the case of this micro-hole forming apparatus, two micro-holes forming sections are provided and a laser beam aimed from a single laser source is split into two laser beams and these two laser beams are introduced into the two micro-hole forming sections. The cigarettes carried are also introduced to these two micro-holes forming sections where the laser beams are focused onto the cigarettes to form the micro-holes thereon The high speed production of cigarettes is thus performed.
In the case of the micro-hole forming apparatus provided with these two micro-hole forming sections, it is required that the micro-holes formed by each of the micro-hole forming sections are kept under a certain standard to keep the quality of the cigarettes high. In order to meet this standard, it is required that the laser beam aimed from the single laser source is split into the two laser beams which are substantially equal in light intensity, and a micro-hole forming apparatus which can meet this standard is realized.
Even if the laser beams split are equal in light intensity, it does not necessarily follow that those micro-holes which are under the certain standard can be formed on the cigarettes at the two micro-holes forming sections. It is therefor still possible that the micro-holes formed are different for every cigarette. This makes it desirable to examiner or check the micro-holes formed.